Tests coverage tool

The Tests Coverage Tool is a comprehensive utility designed to measure code coverage for gRPC services based on their proto contracts. It provides detailed insights into various aspects of your service's coverage, helping you ensure that your tests thoroughly validate your gRPC endpoints. The tool gathers the following metrics:

• Total Coverage Percentage: The overall coverage percentage across all services;
• Service-Specific Coverage: The coverage percentage for each logical service within your gRPC API;
• Method Coverage: Whether each gRPC method is covered by tests (covered/not covered);
• Request/Response Coverage: Detailed coverage for each method, including the total request parameters, the number of covered parameters, and the coverage percentage;
• Parameter-Level Coverage: In-depth coverage details for each parameter within the request/response, allowing you to see which parts of your API are thoroughly tested;
• Deprecation Status: Information on whether methods and their parameters are deprecated, aiding in maintaining up-to-date and clean tests;
• Support for Multiple Services: The tool can handle coverage reporting for multiple gRPC services within a single project;
• Coverage history: The tool can maintain the history of overall service coverage, logical service coverage, and coverage of gRPC method request and response parameters.

You can see a report example here.

If you have any questions, you can ask @Nikita Filonov

Preview

Service coverage

Logical services coverage

Method coverage

Installation

To install the Tests Coverage Tool, use the following command:

go get github.com/Nikita-Filonov/tests-coverage-tool@latest

Usage

Client interceptor

Below is an example of how to set up the gRPC client with the coverage interceptor:

package test

import (
	"context"
	"crypto/tls"
	"fmt"
	"log"
	"testing"

	grpcmiddleware "github.com/grpc-ecosystem/go-grpc-middleware"
	"google.golang.org/grpc"
	"google.golang.org/grpc/credentials"

	"github.com/Nikita-Filonov/tests-coverage-tool/tool/coverageinupt"
)

func TestGRPC(t *testing.T) {
	// Set up a gRPC client connection with the coverage interceptor
	conn, err := grpc.Dial(
		"localhost:1000",
		grpc.WithTransportCredentials(credentials.NewTLS(&tls.Config{InsecureSkipVerify: true})),
		grpc.WithUnaryInterceptor(
			grpcmiddleware.ChainUnaryClient(
				// Integrate the CoverageInterceptor to track method coverage
				coverageinupt.CoverageInterceptor(),
			),
		),
	)
	if err != nil {
		log.Fatalf("Failed to connect to gRPC server: %v", err)
	}
	defer conn.Close()

	// Initialize the proto service client
	client := servicev1.NewServiceClient(conn)

	// Call a gRPC method; coverage data will be automatically saved in the specified directory
	resp, err := client.Get(context.Background(), &servicev1.GetRequest{})

	fmt.Println(resp, err)
}

Generate report

Before generating the coverage report, ensure that the tests-coverage-tool is installed. This tool relies on server reflection to gather data, so your gRPC service must support server reflection; otherwise, the tool will be unable to measure service coverage.

To install the tool, run:

go install github.com/Nikita-Filonov/tests-coverage-tool/...@latest

Once installed, you can generate the coverage report with the following command:

tests-coverage-tool save-report

This will generate a coverage report based on the results gathered during your test runs.

Config

The tool can be configured via environment variables or a YAML configuration file. Below are the available options:

Environment	YAML	Default	Example
—	services	—	Defines the gRPC services to monitor. See the example configuration file at ./docs/config-example.yaml
TESTS_COVERAGE_CONFIG_FILE	—	—	Path to the YAML configuration file. Example: ./docs/config-example.yaml
TESTS_COVERAGE_RESULTS_DIR	resultsDir	.	Directory where coverage results will be stored. Example: if set to ./tests, results will be stored in ./tests/coverage-results
TESTS_COVERAGE_HISTORY_DIR	historyDir	.	Directory where the history will be saved
TESTS_COVERAGE_HISTORY_FILE	historyFile	coverage-history.json	Name of the history file
TESTS_COVERAGE_HTML_REPORT_DIR	htmlReportDir	.	Directory where the HTML report will be saved
TESTS_COVERAGE_JSON_REPORT_DIR	jsonReportDir	.	Directory where the JSON report will be saved
TESTS_COVERAGE_HTML_REPORT_FILE	htmlReportFile	index.html	Name of the HTML report file
TESTS_COVERAGE_JSON_REPORT_FILE	jsonReportFile	coverage-report.json	Name of the JSON report file
TESTS_COVERAGE_HISTORY_RETENTION_LIMIT	historyRetentionLimit	30	Defines the maximum number of the most recent coverage history records to be retained. In this case, the value 30 means that only the latest 30 entries in the coverage history will be preserved, and older entries will be discarded.

History

To save coverage history, you must retain the history file, which is configured using the environment variables TESTS_COVERAGE_HISTORY_DIR and TESTS_COVERAGE_HISTORY_FILE. By default, the history file will be stored in the root directory with the name coverage-history.json. You do not need to create this file manually—it will be automatically generated when you run the save-report command. After that, you simply need to keep the coverage-history.json file for subsequent report generations. Each time a new report is generated, the file will be automatically updated with the latest coverage history, and the history will be added to the coverage report.

If you wish to disable the coverage history functionality, you can set the TESTS_COVERAGE_HISTORY_DIR and TESTS_COVERAGE_HISTORY_FILE environment variables to empty strings. This can be done through the YAML configuration file using the historyDir and historyFile settings.

Commands

Save report

To save a coverage report, use the following command:

go run ./tests-coverage-tool/main.go save-report

This command will generate and save the coverage report based on the collected test data.

Copy report

To update and merge submodules and then copy the report, run:

git submodule update --init --recursive
git submodule update --remote --merge

go run ./tests-coverage-tool/main.go copy-report

This command is useful for syncing submodules and copying the report to the desired location.

Print config

To print the current configuration, use the following command:

go run ./tests-coverage-tool/main.go print-config

This command outputs the configuration settings currently in use, allowing you to verify and adjust as needed